The insertion ratio of the diaphragm wall is crucial for the deformation control of the deep excavation of a subway station in water‐rich soft soils. Taking the deep excavation project of a subway station in water‐rich soft soils as the background, a flow–stress coupling finite element analysis model is established to describe the combined effect of deep excavation and dewatering based on the Biot consolidation theory. The general characteristics of the coupling deformation of dewatering and excavation are studied, and the influence of the insertion ratio of the diaphragm wall on the ground deformation is analyzed. The results show that (1) both dewatering and deep excavation can cause lateral displacement of the diaphragm wall toward the pit, and the dewatering‐induced settlement dominates the total settlement, as compared with that induced by excavation. (2) With the increase of the insertion ratio of the diaphragm wall, the maximum lateral displacement of the diaphragm wall under excavation gradually decreases until it converges to a constant, while the maximum lateral displacement under dewatering and excavation decreases first and then increases. (3) The relationship between the maximum ground settlement and the insertion ratio of the diaphragm wall shows a similar development trend to that between the lowest dewatering head and the insertion ratio of the diaphragm wall, which is approximately linear when the insertion ratio of the diaphragm wall is between 1.1 and 2.3. The control of hydraulic head outside the pit by the diaphragm wall is an effective way to reduce the ground settlement, which has a positive effect on reducing the construction risk and cost in water‐rich soft soils.
Wang et al. (2025) studied this question.